166 Thirty-second Report on the Staie Museom. 



Cell-pores in two ranges, broad-oval or round, very closely arranged, opening 

 slightly obliquely outward, and but very slightly upward ; from four to six in 

 the space of a fenestrule; cell-margins thin, elevated, slightly indenting the 

 border of the fenestrule ; pores in the opposite ranges alternating ; space between 

 ranges of pores not carinated in some cases, in others very slightly carinated, or 

 obtusely angular ; obscurely striated, and occasionally a line of obscure nodes. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 

 Fenestella iEsYLE, n. sp. 



(I'LATE XIX, FIGS. 11-13.) 



Bryozoum fan-shaped. Branches slender, rapidly diverging ; from eight to 

 ten in the space of five mm., but very slightly enlarging below bifurcations, 

 which are frequent and irregular. 



Dissepiments slender, from one-half to two-thirds the width of the branches ; 

 six in the space of five mm., but slightly expanding at their junction with the 

 branches. 



Fenestrules variable in size and shape, generally subquadrangular ; width 

 varying from once to three times that of the branches ; poriferous side unknown. 



Formation and locality. Lower Helderberg group, near Clarksville. N. Y. 

 Fenestella Idothea, n. sp. 



(PLATE XIX, FIGS. 14, 15.) 



Polypora elegans 9 Hall. Twenty-sixth Rep. N. Y. St. Mus. Nat. Hist., p. 97. 1874. 



Bryozoum palmate. Branches moderately strong, rounded, frequently and 

 irregularly bifurcating ; non-poriferous side unknown. 



Dissepiments slender ; width from less than one-half that of the branches to 

 nearly equal ; six in the space of five mm., scarcely expanding at their junc- 

 tion with the branches. 



Fenestrules variable in shape, mostly subquadrangular ; width slightly more 

 than that of the branches ; length from once and one-half to twice the width. 



Cell-pores in two alternating ranges, opening nearly directly outward ; open- 

 ings circular or slightly oval ; distance from each other equal to their diameter ; 

 three in space of a fenestrule ; margins slightly elevated, scarcely indenting the 

 borders of the fenestrules ; space between ranges of pores not carinated ; rounded ; 

 tortuously striated ; dissepiments also striated. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y„ 

 Fenestella Alth^ia, n. sp. 



(PLATE XIX, FIGS. 17-19.) 



Bryozoum — only fragments have been so far observed, so that the form of the 

 whole frond is not certainly known. Branches slender ; bifurcations compara- 



